Adaptive voltage positioning (sometimes referred to as AVP) has been implemented in power supply circuitry to provide better transient response and reduce the number of output filter capacitors. For example, adaptive voltage positioning includes modifying an operating setpoint of a power supply such that the output voltage is higher than a nominal value during conditions in which the current supplied to the load is relatively low. The output voltage of the power supply is controlled to be lower than the nominal value during conditions in which the current supplied to the load is relatively high. Accordingly, the output voltage of a power supply implementing adaptive voltage positioning varies depending on the amount of current consumed by the dynamic load.
To implement adaptive voltage positioning, the vast majority of conventional power supply control circuits use a standard analog control loop. Such control loops typically include an analog buffer amplifier, analog error amplifier (which acts as the control loop filter with external compensation components), a ramp generator (per phase), and a comparator (per phase). Other analog components have been used in the prior art to implement phase balancing and fault detection.
FIG. 1 is an example diagram illustrating a summer circuit 100 for controlling the output of a power supply according to the prior art. As shown, the summer circuit 100 includes both analog components and digital components. The circuit includes multiple analog-to-digital converters.
FIG. 2 is an example diagram illustrating a hypothetical output impedance of the power supply circuit in FIG. 1. As shown, the DC output impedance for the power supply circuit 100 is non-linear due to the errors present in the analog-to-digital converters 101 and 102 of FIG. 1.